The 'Supergirl' Stars Spill Details About Tonight's Dramatic Episode

"Supergirl" has come a long way this season since coming out as a super-powered alien bent on protecting National City from evil, and so has the CBS show's titular lead Melissa Benoist.

"I feel myself getting stronger," the young actress, who plays Superman's cousin Kara Zor-El, told Moviefone at an on-set press junket. "Which matches the trajectory Supergirl is on... She started off as this rhino, charging at things [without much] aim or focus. Now she's really zoning in on a target."

Unfortunately, just as she's finally figuring out her powers, National City's newest hero must suddenly learn to learn to live without them. Monday's episode "Human for a Day" sees Kara stripped of her super abilities, thanks to last week's epic but draining battle with Red Tornado.

Executive producer Andrew Kreisberg explained how the showrunners came up with the dramatic twist: "It is something that is actually sort of new from the comics. It was a [Marvel COO] Geoff Johns' idea, which was that Superman or any Kryptonian's cells are basically suffused with solar radiation and that's where they get their powers from, and heat vision is an expulsion of that energy... so you could just basically run out and you would need to recharge."

Kara might not be able to fly, punch through walls, or heat coffee with her eyes, but she's also not the type to take a sick day when it comes to saving her city. "Obviously, it's kind of a frustrating feeling," Benoist admitted. "But I think the whole point of [Monday's episode is] you don't need powers to be a hero. What is in Kara's heart is what makes her a hero."

Calista Flockhart, who plays Kara's hardnosed boss Cat Grant, may have inadvertently helped prepare her for being powerless. She says Cat has been cultivating Kara's inner strength all season long, despite not even knowing she moonlights as Supergirl.

"Cat sees something special in Kara, [which is why she] tells her what to do by being nasty and suggesting it in her own way," Flockhart said. "So it doesn't sound like advice."

Mehcad Brooks, who plays Superman's famous pal and Kara's crush James "Jimmy" Olsen, expressed similar sentiments: "[Supergirl] is still the hero," he said. "The cool thing about the episode is you realize you don't need powers to be a hero."